Insurance underwriting is basically your insurer figuring out how likely you are to die during your contract with them, and then giving you a price based on that risk. The life insurance underwriting process confirms if you're eligible for coverage, the amount you can buy, if there'll be any restrictions on your policy, and of course, how much it'll cost you.
You can learn more about underwriting via our Insurance underwriting: what’s with all the questions? blog post.